Tech stocks on display at the Nasdaq.Peter Kramer | CNBCAlphabet and Tesla climbed to fresh records on Wednesday, closing at all-time highs alongside Amazon and Meta as the tech megacaps lifted the Nasdaq past 20,000 for the first time.Tech's seven trillion-dollar companies added roughly $416 billion in market cap for the day.For Alphabet, the two-day 11% rally was driven by the company's launch of its latest quantum computing chip, which it revealed on Monday and described as a "breakthrough" a...